From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: [PATCH 14/14] dm, dm-mpath: Make it easier to detect unintended I/O request flushes Date: Fri, 18 Nov 2016 14:30:29 -0800 Message-ID: <98a99f41-e2c5-e65f-d298-1b56403910c1@sandisk.com> References: <32edbd52-5b1a-b093-0195-2ec6fa73cd6f@sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <32edbd52-5b1a-b093-0195-2ec6fa73cd6f@sandisk.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Mike Snitzer Cc: device-mapper development List-Id: dm-devel.ids I/O errors triggered by multipathd incorrectly not enabling the no-flush flag for DM_DEVICE_SUSPEND or DM_DEVICE_RESUME are hard to debug. Add more logging to make it easier to debug this. Signed-off-by: Bart Van Assche --- drivers/md/dm-mpath.c | 25 +++++++++++++++++++++---- drivers/md/dm.c | 3 +++ 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 4a3afec..c3d7e3e 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -489,6 +489,23 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) } /* + * Note: dm_report_eio() is a macro instead of a function to make pr_debug() + * report the function name and line number of the function from which it has + * been invoked. + */ +#define dm_report_eio(m) \ +({ \ + struct mapped_device *md = dm_table_get_md((m)->ti->table); \ + \ + pr_debug("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d\n", \ + dm_device_name(md), \ + test_bit(MPATHF_QUEUE_IF_NO_PATH, &(m)->flags), \ + test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &(m)->flags), \ + dm_noflush_suspending((m)->ti)); \ + -EIO; \ +}) + +/* * Map cloned requests (request-based multipath) */ static int __multipath_map(struct dm_target *ti, struct request *clone, @@ -510,7 +527,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, if (!pgpath) { if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) return DM_MAPIO_DELAY_REQUEUE; - return -EIO; /* Failed */ + return dm_report_eio(m); /* Failed */ } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { pg_init_all_paths(m); @@ -612,7 +629,7 @@ static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_m if (!pgpath) { if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) return DM_MAPIO_REQUEUE; - return -EIO; + return dm_report_eio(m); } mpio->pgpath = pgpath; @@ -1536,7 +1553,7 @@ static int do_end_io(struct multipath *m, struct request *clone, if (atomic_read(&m->nr_valid_paths) == 0 && !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) - r = -EIO; + r = dm_report_eio(m); return r; } @@ -1580,7 +1597,7 @@ static int do_end_io_bio(struct multipath *m, struct bio *clone, if (atomic_read(&m->nr_valid_paths) == 0 && !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) - return -EIO; + return dm_report_eio(m); /* Queue for the daemon to resubmit */ dm_bio_restore(get_bio_details_from_bio(clone), clone); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index d19c372..08a21d1 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2098,6 +2098,9 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, */ if (noflush) set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); + else + pr_debug("%s: suspending without no-flush flag\n", + dm_device_name(md)); /* * This gets reverted if there's an error later and the targets -- 2.10.1